Bigquery选择不同的值

Question

如何在Google BigQuery中选择不同的值？

查询：

SELECT DISTINCT cc_info 
FROM user 
WHERE date = ? 

谢谢！

Answer 1

SELECT cc_info 
FROM user 
WHERE date = ? 
GROUP BY cc_info 

Answer 2

尝试使用group by

SELECT cc_info 
FROM user 
WHERE date = ? 
group by cc_info 

Answer 3

只要使用由组，

SELECT cc_info 
FROM user 
WHERE date = ? 
GROUP BY cc_info 

如果你想数着你可以使用不同的值，

SELECT COUNT(DISTINCT cc_info) 
FROM user 
WHERE date = ? 

Answer 4

SELECT COUNT(DISTINCT cc_info) 
FROM user 
WHERE date = ? 

是不是正确的查询，因为DISTINCT是统计近似值，并不保证是确切的。见https://cloud.google.com/bigquery/docs/reference/legacy-sql#countdistinct

因此，更好的办法是

select EXACT_COUNT_DISTINCT(cc_info) from user where date = ?